Matrix switch



Oct. 24, 1967 J. M. CARTELLI MATRIX SWITCH 3 Sheets-Sheet 1 Filed Oct. 2, 1964 INVENTOR JOSEPH M. CARTELLI ATTORNEYS Oct. 24, 1967 J. M. CARTELLI MATRIX SWITCH 3 Sheets-Sheet 2 Filed Oct. .2, 1964 FIGB FIG?

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- ATTORNEYS United States Patent 3,349,361 MATRIX SWITCH Joseph M. Cartelli, 103 Ascan Ave., Forest Hills, N.Y. 11375 Filed Get. 2, 1964, Ser. No. 4%,939 18 (Jlaims. (6!. 339-18) This invention relates to matrix switches, sometimes called pin boards or program boards, in which multiple layers or decks of conductors may be connected at desired points by slidably inserted pins.

Heretofore such matrix switches have been expensive, often requiring complex metal channels on spaced-apart decks. A general object of the present invention is to improve matrix switches, and to provide a matrix switch structure which is simple and compact. The decks may be assembled in face-to-back contact without spacers or spacer boards. The pins may be ordinary solid metal pins, although coaxial and other special pins may be provided for special purposes. The contact strips are simple flat strips, available at minimum cost.

A further object is to apply the improved structural features not only to a standard matrix switch, but also to special switches such as computer-coded output switch for binary-to-decimal conversion.

Another object is to provide for external connections, to either the front or the back of the switch, and to more than two decks.

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, my invention resides in the matrix switch elements and their relation one to another, as are hereinafter more particularly described in the following specification. The specification is accompanied by drawings in which:

FIG. 1 is a perspective view showing a matrix switch embodying features of the invention;

FIG. 2 is a fragmentary perspective view explanatory of the construction of a single deck;

FIG. 3 is a fragmentary horizontal section showing the relation of the deck holes and strips to a top plate hole and pin;

FIG. 4 is a fragmentary section taken on the stepped line 44 of FIG. 3;

FIG. 5 is a similar section through a modification;

FIG. 6 is a fragmentary horizontal section showing the modification of FIG. 5;

FIG. 7 shows a fragmentary part of a deck having rectangular holes;

FIG. 8 is a fragmentary view showing one method of anchoring the strips against longitudinal movement;

FIG. 9 is a fragmentary plan view with some decks broken away to show the use of terminal pins at the ends of the strips;

FIG. 10 is a fragmentary vertical section taken approximately on the stepped line 10-10 of FIG. 9, and shows how the upper decks are broken away at the right;

FIG. 11 is a perspective view of one of the terminal pins used in FIGS. 9 and 10;

FIG. 12 is a bottom View drawn to very small scale, and shows the use of terminal pins at both ends of each strip;

FIG. 13 is a similar bottom view showing the use of terminal pins at one end only of each strip;

FIG. 14 is a vertical section showing a coaxial pin which may be used for some purposes, such as the interposition of a component;

FIG. 15 is a section through a special pin which is long and has separated contact sleeves;

FIG. 16 is a fragmentary section through a four-deck matrix, taken on the angle line 16-16 of FIG. 17, and showing the use of terminal pins of different length;

approximately 3,349,361 Patented Oct. 24, 1967 FIG. 17 is a plan view of one corner of the four-deck matrix switch shown in FIG. 16;

FIG. 18 is a perspective view of a computer-coded output switch;

FIG; 19 is a schematic diagram showing the relation of the superposed strips for binary-to-decimal conversion in the switch of FIG. 18, taken on the line 1919 of FIG. 18; and

FIG. 20 is a fragmentary view of one of the decks in the computer-coded output switch.

Referring to the drawing, and more particularly to FIG. 1, the matrix switch 12 is generally conventional in comprising superposed boards with an array of holes 14 into which pins 16 may be inserted to establish desired con nections. In the present switch the boards or decks are superposed directly in back-to-face relation, and require no spacers nor separation plates.

One characteristic feature of the new construction may be described with reference to FIG. 2, which is a fragmentary view of one deck. The deck comprises an insulation board 18 having an array of holes 20 passing therethrough, and having parallel slots 22 intersecting the holes. The slots 22 have a depth less than the thickness of the board 18. A resilient metal strip 24 is received edgewise in each slot, and these strips have a height no greater than the depth of the slots. It will be seen that the strips bridge the holes, and that multiple decks may be superposed face-to-back. An upper deck covers a lower deck and holds the lower strips in position. The slots are thin, and the strips 24 are made of thin resilient metal. In the preferred form illustrated, the slots and strips cross the holes diametrically.

Referring now to FIGS. 3 and 4, a strip 26 of one deck is electrically connected to a strip 28 of another deck by insertion of a metal pin having a shank 30 of uniform diameter. The holes 32 and 34 in the decks are about double the diameter of the pin 30, and are so dimensioned that the strips are slightly deflected by the pin. When, as is usual, the strips of one deck are perpendicular to those of an adjacent deck, the holes and strips are offset from the axis of the pin an amount such as to receive the pin. Usually there is a top plate 36, as shown in FIGS. 3 and 4, and in such case the hole 38 in the top plate is dimensioned to receive the pin, and it has a diameter only about half the diameter of the holes in the deck. The top plate and the decks are so assembled that the deck hole 32 is offset downwardly (as viewed in FIG. 3) from the hole 38, that is, in a direction perpendicular to its strip 26; and the deck hole 34 is offset sidewardly from the hole 38, again in a direction perpendicular to that of the strip 28. This will be understood from inspection of FIGS. 3 and 4, but it is important to understand the the hole location in the top plate 36 is not needed to cause the pin to bear resiliently against the strips. The pin diameter alone accomplishes that, because it slightly exceeds the space available between the side of the strip and the side of the deck hole between which the pin is pushed. The pin deflects the resilient strip at its midspan, as shown in FIG. 3. The primary purpose of the top plate is to lock the top strips in the slots. Another purpose is to guide the user when inserting a pin, the matrix being marked for that purpose. It also improves the appearance of the switch.

Referring next to FIGS. 5 and 6 of the drawing, in this case the large holes 40 of the decks are coaxial with the small hole 42 of the top plate 44. However, the strips 46 and 48 are oifset from the axis of the holes and pin. In FIG. 6, the strip 46 is offset upwardly an amount appreaching but somewhat less than the radius of the pin. Similarly, the strip 48 is offset sidewardly an amount somewhat less than the radius of the pin. The slots and strips are offset relative to the holes and therefore are not diametrical of the holes. However, they do receive the pin 50, and they are deflected slightly by the pin, for good electrical contact and frictional grip.

It will be noted that in this case the deflection is produced by the position of the pin itself, and therefore the pin preferably fits the top hole 42 rather closely so that the pin will be held in proper alignment. For this construction it may be preferred to add a perforate bottom plate, the bottom plate having small diameter holes in alignment with the holes in the top plate. The pin then is lengthened to extend into the bottom plate, so that the pin is supported at both ends against the reaction of the deflected resilient strips. However, the bottom plate is not essential.

The holes need not be round, and FIG. 7 illustrates a deck 54 having rectangular holes 56. The long dimension of the hole extends in the direction of the slots and strips, and the strips are preferably offset to a position near one of the longer sides of the deck holes, as shown by strip 58 and slot 60. The distance between strip 58 and the remote side 62 of the hole is preferably made somewhat less than the diameter of pin 64, so that the pin deflects the strip by reaction against the side 62 of the hole. The other side 66 of the hole may be so located as to limit the maximum permissible deflection of the strip 58, thereby protecting the strip against possible abuse. This protection is not essential.

With this arrangement, as in the case of the offset round holes shown in FIGS. 3 and 4, a top plate is not essential to position a pin, because structurally the pin provides a deflection force against the deck itself, in this case against the side 62 of the hole 56. It holds the strips and is a pin-location guide, and acts as a dress plate, as previously explained. I p

It may be mentioned that the decks may be manufactured by punching holes through an insulation plate, or by a molding operation. The round holes have the advantage of minimizing die expense. When the decks are manufactured in large quantity, by a direct molding operation which forms the holes, or the holes and slots, as a part of the molding operation, it may be preferred to use holes which are not circular. The holes may be rectangular, as shown in FIG. 7. The holes may be triangular, with the contact strip extending along one side of the triangle, while the pin bears against the other two sides to deflect the strip. In all cases the deck holes could be enlarged, and reliance be had on top and bottom plates to fix the location of the pin, as was described in connection with FIGS. and 6, and regardless of the hole shape.

FIG. Sillustrates one method of anchoring the strips. In this case the strips 68 are reversely bent to form an enlargement 70 which is located in endmost hole 72. This fixes the metal strip against excessive longitudinal movement, even when the slots extend to the end of the deck as shown at 74. When the slots are formed by a cutting operation it is convenient to carry them all the way through to the ends of the deck, as shown in FIG. 8. The strips should be free to move slightly longitudinally to accommodate the deflection when a pin is inserted.

A somewhat more elaborate way of terminating the strip and also providing a terminal connection to the strip may be described with reference to FIGS. 9, 10, and 11 of the drawing. The illustrated structure has two decks, with offset holes of the type described with reference to FIGS. 3 and 4. In FIG. there is a top plate 76, an upper deck 78, a lower deck 80, and a bottom plate 82. The left end 84 (FIG. 9) of the strip 86 is deflected by a terminal 88. In FIG. 9 only two of the crossed strips are shown in the slots.

Referring to FIG. 11, the terminal 88 has a largediameter anchor portion 98, in addition to the contact portion 88, and shank 92. The anchor portion 90 is preferably otfset or eccentric relative to the parts 88 and 92,

and is dimensioned in axial direction to be received beneath the strip 86.

Referring now to FIG. 10, the eccentric or anchor part is dimensioned to fit below the strip 86, and to substantially fully occupy the lower half of the largediameter hole in the deck 78. The shank 92 projects downward through the bottom plate 82, and preferably has a hole 94 dimensioned to receive an external electrical connection. This may be done by means of a pin jack inserted in the hole, or by soldering a wire in the hole. Inasmuch as the hole in deck 88 is offset from the hole in deck 78, the anchor portion 98 secures the terminal pin against movement downward. Strip 86 holds it against movement upward.

Reverting to FIG. 9, the diameter of the part 88 of the pin may be the same as the diameter of an ordinary inserted contact pin, but preferably it is somewhat increased in diameter for increased deflection of the end 84- of strip 86. This is done because in the end hole the strip is anchored at only one side of the hole, instead of both.

In similar fashion the strip 96 may have its end 98 deflected by a terminal pin 108. Referring now to FIG. 10, this terminal pin 180 is shorter because its upper end extends only to the strip 98 of the lower deck 88, instead of to the upper deck 78. The part 188 bears against the strip 98; the eccentric or anchor part 102 is locked between the strip 98 and the bottom plate 82; and the part 104 is short, as shown. The terminal pin again has a hole 186 for external connection, as previously described.

FIG. 12, drawn to very small scale, shows how the bottom 82 may have lines of the longer terminal pins 88 extending along two edges, and lines of the shorter terminal pins extending along the other two edges. This assumes each strip to be terminated by a terminal pin at both ends. The strips may have a terminal pin at only one end, combined with a reversely bent hook (as shown in FIG. 8) at the other end, and this is illustrated in FIG. 13, in which there is a line of terminal pins 88 along one edge, and a line of terminal pins 108 along another edge. The structure of FIG. 13 is a little less expensive than that of FIG. 12, but the latter has the advantage that a greater number of external wires may be connected to any strip of the matrix switch. If desired, the matrix may be extended by positioning another matrix alongside, with bridging connections from one matrix board to the adjacent matrix board. For this purpose the double terminals of FIG. 12 would be preferred.

It will be understood that the terminal pins may extend upward instead of downward, with connections at the top instead of at the bottom. However, the illustrated arrangement is more common because the matrix switch is usually exposed as a panel, with the perforated front available for the insertion of desired contact pins, while the permanent wiring is at the back of the panel, and therefore the terminal pins are exposed at the back or bottom, as shown in FIGS. 10, 12, and 13.

As so far described the terminal pins have been applied to a switch having two decks. When there are more decks the terminal pins may be appropriately modified. FIG. 16 shows a switch having a top plate 118, four decks 112, 114, 116, 118, and a bottom plate 120. The section is an angle section in one corner, as though taken on the angle line 16-16 of FIG. 17. Two rows of holes along the edge are used solely for terminal pins. The strip 122 (FIG. 16) of the deck 112 is terminated by a terminal pin 124 having an anchor part 126 which is of large diameter and eccentrically related, as shown in FIG. 11. The shank 128 is long enough to reach through the bottom plate 128, and again is counterbored with a hole 130 for external connection. The shank 128 does not contact the transverse strips (vertical strips as viewed in FIG. 17), because these stop two rows of holes short of the edge of the switch (much as in FIG. 12 the upright strips stop one row of holes short of the left and right edges of the switch, so that there is no contact with terminal pins 88).

The contact strip 136 of deck 116 is electrically terminated by a terminal pin 138 having an eccentric anchor part 140 and a shank 142. The strips 136 are shorter than the strips 122 by one row of holes, as shown in the drawing. Shank 142 has a reentrant hole for a wire connection, as before.

In similar fashion, contact strip 144 of deck 114 is terminated by a terminal pin 146 having an eccentric anchor part 148 and a shank 150, the length of which carries it through bottom plate 120. The contact strip 152 of deck 118 is terminated by a terminal pin 154 having an anchor part 156 and a shank 158. Shanks 150 and 158 have holes, as before. The section shown in FIG. 16 is an angle section, it being understood that rows of the terminal pins 124 and 138 would extend along one edge of the switch, while rows of the terminal pins 146 and 154 would extend along another and transverse edge of the switch. The alternate decks have crossed contact strips. There is a terminal pin like 124 for each strip in deck 112; a terminal pin 138 for each strip in deck 116; a terminal pin 146 for each strip in deck 114; and a terminal pin 154 for each strip in deck 118.

As so far described it has been assumed that the slidable contact pins (as in FIGS. 1-7) are solid metal pins, and in most cases they may be. However, special slidable pins may be provided, and FIG. 14 illustrates a coaxial pin in which the lower portion 162 engages a contact strip 164 and is insulated by an insulation sleeve 166 from a hollow metal sleeve 168. This engages contact strip 170 of another deck. In this way external connections to a unit 172 may be provided, as shown in dotted lines by conductors 174 and 176. In many cases the component 172 is so miniaturized that it may be mounted directly at the top of the pin in lieu of an ordinary handle portion; and thus a component such as a diode or a resistor may be interposed directly in the circuit.

Referring now to FIG. 15, the pin 180 is long enough for use with four decks, as shown in FIG. 16. A metal sleeve 182 is insulated from a metal sleeve 184 by means of an insulation shank 186, and thus the pin illustrated would serve to connect a first and second deck, and also a third and fourth deck, without connecting the upper two decks to the lower two decks. While not illustrated, it will be understood that a single metal sleeve might be so located as to connect the second and third decks; or a sleeve might be dimensioned to connect three decks but not a fourth deck. A plain pin would connect all four decks.

Reverting to FIG. 16, in some cases the bottom plate 120 may be provided with a terminal socket 190 having a split resilient portion or socket 192 adapted to receive the lower end of a pin inserted from above. In such case, the contact strips may be connected to the terminal 190 by means of a pin, or selected ones of the contact strips may be so connected by making the pin of special character, as shown in FIG. 14 or FIG. 15. In all cases the pin is lengthened and is given a metal end long enough to be received in the socket 192.

As so far described it has been assumed that the contact strips are in crossed relation. This is not always essential, and for one particular purpose the matrix switch is made with parallel slots and strips. This refers to a computer-coded output switch illustrated in FIGS. 18, 19, and 20. It is designed for binary-to-decimal conversion, and in FIG. 18 the panel is ten holes high, providing for digits from 0 through 9, as illustrated. The five lines of holes shown and lettered A through E provide five integers to a maximum value of 99999. With the pins placed as shown, the number set up is 015 83.

The decimal numbers require combinations of four strips, with a fifth strip for common connection. (This could provide sixteen combinations, but only ten are used for decimal numbering.) The strips in one deck, in this case the top deck, may be straight, and are used for a common connection, as represented in FIG. 19 by strip 200. The remaining strips are bent to arcuate shape around a half periphery of some holes to avoid contact with a pin, and are straight across other holes for contact with a pin, the location of the bent and straight parts being difierent in the different superposed strips, and in such fashion as to provide the desired binary-to-decimal conversion.

Referring to FIG. 20, the deck 202 has large holes 204 and 206 with a slot running diametrically therethrough, as described in connection with FIGS. 3 and 4. The large holes are offset relatively to the pin 208, and the dimensioning of the parts is such as to deflect a straight strip, as shown. Where no contact is to be made, the strip is bent around the remote half of the hole, as shown at 210, thereby displacing it from any possible contact with the pin, located at 208'. Although the large holes are offset from the pins and the small holes of the cover plate, the large holes of the four decks are in alignment with one another.

Reverting to FIG. 19, the strips 212, 214, 216, and 218 may be bent or left straight, as indicated, so that an inserted pin will make certain combinations of connections. Only one pin is inserted in one line of holes, and in FIG. 19 the pin is being used at the number 3, corresponding to a cross section taken on the line 1919 in FIG. 18. The other possible pin locations from zero to nine are indicated.

It will be understood that the switch shown in FIG. 18 would in all cases be ten holes high for decimal purposes; would in all cases have five decks for binary conversion; but may be reduced or extended from left to right according to the number of integers desired for the maximum numerical capacity of the switch. In FIG. 18 there are five integers, but there could be less or more.

As one example of dimensioning of the parts, the matrix switch is currently made with a deck which is inch thick, receiving contact strips which are inch wide. The contact pins have a diameter of 0.106 inch, and the deck holes have a diameter of 0.210 inch, and are ofiset by 0.05 3 inch. The small holes in the top plate have a diameter of 0.110 inch. The terminal pin which bends and thereby locks the end of a contact strip has a diameter of 0.120 inch. The switch shown in FIG. 1 has eighty cross points, and such switches have been made from twenty cross points on up to eleven thousand points. It will be understood that the specific dimensions have been given by way of example, and are not intended to be in limitation of the invention.

It may be mentioned that two decks can be combined in one insulation piece of increased thickness, the said piece having top slots and strips extending in one direction, and bottom slots and strips extending in transverse direction. The top holes extend only partway down through the insulation, and the bottom holes extend partway up through the insulation, these holes being offset as previously described. Such a construction may seem difiicult (but not impossible) when the holes are produced by drilling, but with volume production the insulation piece may be molded, and the oppositely directed offset holes could readily be produced by molding. Such a unit would consist of two decks, even though formed in a single piece of insulation.

When the matrix switch has four decks, it is not essential that the strips alternate in direction, as shown in FIG. 16. Adjacent decks could have parallel strips, the arrangement for the four decks being XXYY instead of XYXY, using the X and Y coordinates to indicate transverse strip orientation. Similarly, the strip arrangement could be XYYX or YXXY or YYXX.

A switch may comprise as little as one deck with contact strips, a top plate, and a bottom plate like the plate in FIG. 16 with terminal sockets like the terminal 190, leading by wires (not shown) to different circuits.

One or more short pins then may be used for connecting any such terminal circuit to a strip in the deck.

The expression binary-to-decimal has been used in connection with FIGS. 18-20, as applied to a so-called BCD switch or binary coded decimal switch. Actually, the pins are inserted decimally, and provide electrical switching which is binary, so that the actual operation is decimal-to-binary.

It is believed that the construction, method of assembly, and method of use of my improved matrix switch, as well as the advantages thereof, will be apparent from the foregoing detailed description. The switch is low in cost. It has a high mechanical environment capacity for MIL applications. -It has low contact resistance and low capacitive cross talk. It provides an attractive and uncluttered panel. The structure is rugged and much like a solid block of insulating material. A wide variety of switching combinations are made available while using standard hardware. It is usable in many different applications.

It will be understood that while I have shown and described the invention in several preferred forms, changes may be made without departing from the scope of the invention, as sought to be defined in the following claims. In the claims, the reference to a metal strip being received edgewise is not intended to exclude cross-sections other than rectangular, such as a strip with rounded edges at the top and bottom, or a flattened round wire, or a wire of elliptical cross-section.

I. claim:

1. A matrix switch comprising a plurality of superposed decks, each deck comprising an insulation board having an array of holes passing therethrough, and having thin slots intersecting said holes, said slots having a depth less than the thickness of the board, a thin resilient metal strip received edgewise in each slot, said strips having a height no greater than the depth of the slots, whereby the strips bridge the holes and may be deflected sideward in a hole by means of a pin inserted through the hole for contact with a side wall of a strip, the arrangement being such that a strip of one deck may be electrically connected to a strip of another deck by insertion of a pin the holes in the decks being substantially larger than the diameter of the pin and so dimensioned that a strip is resiliently defiected by the pin.

2. A matrix switch as defined in claim 1, in which the deck holes are coaxial, and in which the slots and strips of a deck are offset from the center of the holes of that deck.

3. A matrix switch as defined in claim 2, in which the deck holes are rectangular with the long dimension in the direction of the slots and strips, and in which the slots and strips are offset to a position near one of the longer sides of the deck holes.

4. A matrix switch as defined in claim 1, in which the ends of the strips are reversely bent, the reversely bent ends being received in end holes and serving to anchor the strips against longitudinal movement.

5. A matrix switch as defined in claim 1, in which there is a terminal pin contacting the end of a strip for outside connection to the strip, said terminal pin having a contact portion which deflects the end of the strip, and a large diameter anchor portion, the latter being dimensioned to be so received in a deck hole as to anchor the pin against axial movement.

6. A matrix switch as defined in claim 1, in which there is a terminal pin contacting the end of a strip for outside connection to the strip, said terminal pin having a small diameter portion and a large diameter anchor portion, the latter being dimensioned to be received in a deck hole beneath a strip to thereby anchor the pin against axial movement, the exposed end of said terminal pin having a hole to receive an external connection.

7. A matrix switch as defined in claim 1, in which the decks have parallel slots and strips, and in which the strips are bent to arcuate shape around the half periphery of some holes to avoid contact with a pin, and are straight across other holes for contact with a pin, the locations of the bent and straight parts being different in the different superposed strips in such fashion as to provide a binary conversion, whereby the switch acts as a computercoded output switch.

8. A matrix switch as defined in claim 1, in which there are five decks all having parallel slots and strips, and in which the strips are ten holes long, and in which the strips of one deck are straight, and the strips of the other decks are bent to arcuate shape around the half periphery of some holes to avoid contact with a pin, and are straight across other holes for contact with a pin, the locations of the bent and straight parts being different in the different superposed strips in such fashion as to provide a binary-to-decimal conversion, whereby the switch acts as a computer-coded output switch.

9. A matrix switch as defined in claim 3, in which there is a pin having a shank of uniform diameter, and in which the resilient strip bridging the hole is straight before the pin has been inserted, and in which the pin diameter is slightly greater than the distance between the side wall of the strip and the side wall of the hole bridged thereby, so that the pin is backed by the insulation board of the deck as it deflects the strip sideward for good electrical contact between the pin and the strip.

10. A matrix switch comprising a plurality of superposed decks, each deck comprising an insulation board having a rectangular array of holes passing therethrough, and having thin parallel slots intersecting said holes, said slots having a depth less than the thickness of the board, a thin resilient metal strip received edgewise in each slot, said strips having a height no greater than the depth of the slots, whereby the strips bridge the holes and may be deflected sideward in a hole by means of a pin inserted through the hole for contact with a side wall of a strip, the slots and strips of one deck being perpendicular to those of an adjacent deck, the arrangement being such that a strip of one deck may be electrically connected to a strip of another deck by insertion of a pin the holes in the decks being substantially larger than the diameter of the pin and so dimensioned that a strip is resiliently deflected by the pin.

11. A matrix switch comprising a plurality of superposed decks, each deck comprising an insulation board having an array of holes passing therethrough, and having slots intersecting said holes, said slots having a depth less than the thickness of the board, a resilient metal strip received edgewise in each slot, said strips having a height no greater than the depth of the slots whereby the strips bridge the holes, the arrangement being such that a strip of one deck may be electrically connected to a strip of another deck by insertion of a pin, the holes in the decks being about double the diameter of the pin and so dimensioned that a strip is resiliently deflected by the pin.

12. A matrix switch comprising a plurality of superposed decks, each deck comprising an insulation board having a rectangular array of holes passing therethrough, and having parallel slots intersecting said holes, said slots having a depth less than the thickness of the board, a resilient metal strip received edgewise in each slot, said strips having a height no greater than the depth of the slots, whereby the strips bridge the holes, the slots and strips of one deck crossing those of an adjacent deck, the arrangement being such that a strip of one deck may be electrically connected to a strip of another deck by insertion of a pin, the holes in the decks being about double the diameter of the pin and so dimensioned that the strip is resiliently deflected by the pin, the holes and strips of the decks being offset from the axis of the pin an amount such as to receive the pin.

13. A matrix switch comprising a plurality of superposed decks, each deck comprising an insulation board having an array of holes passing therethrough, and having slots intersecting said holes, said slots having a depth less than the thickness of the board, a resilient metal strip received edgewise in each slot, said strips having a height no greater than the depth of the slots, whereby the strips bridge the holes, the arrangement being such that a strip of one deck may be electrically connected to a strip of another deck by insertion of a pin, a perforate cover board over the top deck, the holes in the cover board being dimentioned to receive the pin and being substantially smaller in diameter than the holes in the decks, the strips of the decks being offset from the axis of the pin an amount such that a strip is resiliently deflected by the pin.

14. A matrix switch as defined in claim 13, in which the deck holes of each deck are offset from the cover holes in a direction perpendicular to the direction of its slots and strips, and in which the slots and strips of a deck substantially bisect the holes of that deck.

15. A matrix switch as defined in claim 13, in which the deck holes are coaxial with the cover holes, and in which the slots and strips of a deck are ofiset from the center of the holes of that deck.

16. A matrix switch as defined in claim 13, in which the deck holes are rectangular with the long dimension in the direction of the slots and strips, and in which the slots and strips are offset to a position near one of the longer sides of the deck holes.

17. A matrix switch as defined in claim 13, in which there are five decks all having parallel slots and strips, and in which the strips are ten holes long, and in which the strips of one deck are straight, and the strips of the other decks are bent to arcuate shape around the half periphery of some holes to avoid contact with a pin, and are straight across other holes for contact with a pin, the location of the bent and straight parts being different in the different superposed strips in such fashion as to provide a binary-to-decimal conversion, whereby the switch acts as a computer-coded output switch.

18. A matrix switch comprising a plurality of superposed decks, each deck comprising an insulation board having a rectangular array of holes passing therethrough, and having parallel slots intersecting said holes, said slots having a depth less than the thickness of the board, a resilient metal strip received edgewise in each slot, whereby the strips bridge the holes, the slots and strips of one deck being transverse to those of an adjacent deck, the arrangement being such that a strip of one deck may be electrically connected to a strip of another deck by insertion of a pin, a perforate cover board over the top deck, the holes in the cover board being dimensioned to receive the pin and being about half the diameter of the holes in the decks, the holes and strips of the decks being offset from the axis of the pin an amount such as to receive a pin, and the spacing between a strip and the side of the deck hole receiving the strip being such that the strip is resiliently deflected by the pin.

References Cited UNITED STATES PATENTS 231,708 8/1880 Gilliland 317-112 2,019,625 11/1935 OBrien 317-101 2,990,499 6/1961 Cordes 33918 X 3,021,498 2/1962 Spillar 339-18 3,120,584 2/1964 Grunfelder et a1. 3,151,923 10/1964 Bell et a1 33918 3,212,048 12/1965 Rosenberg et al. 33918 3,225,322 12/1965 Reel 339-48 MARVIN A. CHAMPION, Primary Examiner.

PATRICK A. CLIFFORD, Examiner. 

1. A MATRIX SWITCH COMPRISING A PLURALITY OF SUPERPOSED DECKS, EACH DECK COMPRISING AN INSULATION BOARD HAVING AN ARRAY OF HOLES PASSING THERETHROUGH, AND HAVING THIN SLOTS INTERSECTING SAID HOLES, SAID SLOTS HAVING A DEPTH LESS THAN THE THICKNESS OF THE BOARD, A THIN RESILIENT METAL STRIP RECEIVED EDGEWISE IN EACH SLOT, SAID STRIP HAVING A HEIGHT NO GREATER THAN THE DEPTH OF THE SLOTS, WHEREBY THE STRIPS BRIGDE THE HOLES AND MAY BE DEFLECTED SIDEWARD IN A HOLE BY MEANS OF A PIN INSERTED THROUGH THE HOLE FOR CONTACT WITH A SIDE WALL OF A STRIP, THE ARRANGEMENT BEING 